Liquid cooled housing for rotary piston engines

ABSTRACT

The invention relates to a liquid cooled housing for rotary piston engines, in particular internal combustion, consisting of at least one annular shell and two end parts, the housing having an inlet and an outlet connection for the cooling liquid, and the shell and end parts containing chambers in communication with each other and traversed by cooling liquid.

United States Patent Lechler et al. I

LIQUID COOLED HOUSING FOR ROTARY PISTON ENGINES Inventors: Rolf Lechler,Neckarsulm; Johannes Steinwart, Bad Friedrichshall, both of GermanyAssignees: Audi NSU Auto Union Aktiengesellschaft, Wurttemberg; WankelG.m.b.H., Lindau/Bodensee, Germany Filed: May 28, 1970 Appl. No.: 41,197

Foreign Application Priority Data May 31, 1969 Germany ..P 19 27 859.2

US. Cl. ..l23/8.0l, 123/4132, 123/4179,

165/51, 418/83 Int. Cl. ..F02b 53/00, FOlp 3/00 Field of Search..l23/8.01, 8.41, 41.79, 41.67, 123/4132, 8.07; 418/88, 83; 165/145,169, 51

Y 51 3,691,999 [4 1 Sept-19,1972

' References Cited UNITED STATES PATENTS 2,353,965 7/1944 Meador..4l8/83 X 3,289,647 12/1966 Turner ..4l8/83 X FOREIGN PATENTS ORAPPLICATIONS 974,370 11/1964 Great Britain ..41 8/83 PrimaryExaminer-Manuel A. Antonakas Attorney-Kane, Dalsimer, Kane and Kurucz[57 ABSTRACT The invention relates to a liquid cooled housing for rotarypiston engines, in particular internal combustion, consisting of atleast one annular shell and two end parts, the housing having an inletand an outlet connection for the cooling liquid, and the shell and endparts containing chambers in communication with each other and traversedby cooling liquid.

5 Claims, 6 Drawing Figures PATENTEDSEP 19 m2 3HEET10F 3 INVENTORS ROLFLECHLER JOHA IVNES STE/NWAET BY ATTORNEYS PATENTEDSEPIB m1; 3.991.999

SHEET 2 OF 3 K LU l NvE NTO RS ROLF LECHL ER JOHANNES \STE/NWART ATTORNEYS 0 LIQUID COOLED HOUSING FOR ROTARY PISTON ENGINES In a knownliquid cooled housing German Pat. No. 1,193,303), cooling liquidpassages arranged in the shell parallel to the lengthwise centerline ofthe housing, which passages extend from end to end of the shell withtheir ends in communication with chambers provided in the end parts,which chambers collect the passages into groups in which the passagesare in parallel, some of the chambers being in the form of returnpassages by which the groups of passages in parallel are connected inseries. In this way a zig-zag flow through the shell is achieved,enabling the cooling of the shell to be very accurately matched to thedifferential heat load over the periphery of the shell, so that thethermal stresses and strains to which an internal combustion engineparticularly is exposed in operation can be kept low. To avoid leakageof cooling liquid at the joining surfaces between shell and end parts,both inward into the working spaces and outward, in the knownconstruction each end face of the shell is provided with a toroidalgasket on the outer circumference and a toroidal gasket on the innercircumference of the shell,

each set into matching grooves. This construction has variousdisadvantages, which are to be seen primarily in that working thegrooves for the gaskets represents a substantial outlay if they cannotbe circular but, following the shape of the inner surface of the shell,must take the form of an ellipse or an epitrochoid. The toroidal gasketsmoreover have a comparatively large diameter and are, therefore,expensive to produce. Finally, the installation of such large diametergaskets presents considerable difficulties in assembly.

The problem, therefore, is to avoid the disadvantages outlined above andprovide a housing in which outward and inward leakage of cooling liquidis prevented by simple and inexpensive means. This problem is solved,according to the invention, in that the ports for the cooling liquid inthe joining end faces of the shell and end parts are individually sealedby packing rings encircling each of these openings. By virtue of thisproposal, commercial packing rings of comparatively small diameter canbe used, which despite their greater number are much cheaper than theknown toroidal rings and can be installed with very little expenditureof time and labor at assembly.

If the housing is intended for multiple rotary piston engines, andaccordingly has several shells, with a housing head arranged in eachinstance between neighboring shells, chambers are provided, according tothe invention, in the interhead that connect the cambers of the adjacentshells with each other, the ports for cooling liquid in the joiningfaces of the shells and interparts being again sealed individually bypacking rings encircling said ports.

So that there will not be too many ports to be sealed, it isadvantageous, in place of the simple passage of known arrangement, toprovide larger chambers in the shell connected by one or a few ports ineach end face of the shell to matching ports in the adjacent end partsor interparts.

In rotary piston internal combustion engines, the head load notoriouslyvaries greatly over the circumference of the housing. While the sectorin which the intake and compression phases occur remains comparativelycool, the sector in which ignition, expansion in series, by means of thechambers in the end parts, in i such manner as to traverse first thespark plug sector, then the next sector towards the outlet passage, andthen the sector around the outlet passage. At the same time, the crosssections of the several flow paths may be so proportioned as to providethe highest flow velocity I and hence the most rapid heat removal in thesector of greatest heat load.

Since in multiple rotary piston engines the resistance to the flow ofcooling liquid may be comparatively great, it is expedient in theinterpart or interparts, inaddition to the chambers connecting thechambers of the adjacent shells with each other, to provide a chamber tocarry off some of the cooling liquid flowing in out of the sector aroundthe outlet passage of one of the adjacent shells. The cooling liquid inthis case is thus carried off parallel in the interparts and one endpart.

When the housing according to the invention is used for a rotary pistoninternal combustion engine for vehicle propulsion, it is expedient tobranch off, from the chamber of that end part which effects the firstreversal of the liquid, a supply connection for the heat exchanger ofthe vehicle heating system, its drain connection communicating with thecooling liquid circuit return. Cooling liquid is thus bled for heatingpurposes at a point where there is a maximal pressure drop to thereturn, so that the heat exchanger is traversed at relatively highvelocity. At this point, furthermore, hot water will be available quitesoon after the engine is started, so the the heating system will respondquickly. Since the rotary piston internal combustion engine, by virtueof its shape, is advantageously installed in the vehicle with itslengthwise centerline parallel to the centerline of the vehicle.Consequently, the cooling liquid enters the front end part from theradiator in front, the connection for the heat exchanger is located atthe rear end part, which results in short lines from said end part tothe heat exchanger. In the case of an oil cooler for the cooling liquidtraversing the piston, it is arranged at the front end part so that itwill lie in the airstream and can be connected to the chamber in thefront end part, which effects the second reversal of the cooling liquidin the housing.

An embodiment of the invention in the form of a housing for a doublerotary piston engine of trochoid type will now be described by way ofexample, with reference to the drawings.

IN THE DRAWINGS FIG. I shows a developed section of the housing toexhibit the coolant circuit;

FIG. 2 shows a view of the housing taken in the direction of arrow A inFIG. 1;

FIG. 3 shows a section at the line 3-3 in FIG. 1;

FIG. 4 shows a section at the line 4-4 in FIG. 1;

FIG. 5 shows a view of the right-hand end part of FIG. 1 in thedirection of arrow D; and

FIG. 6 shows a section at the line 6-6 in FIG. 3.

The liquid cooled housing shown consists of two end parts 1 and 2, aninterpart 3 and two annular shells 4a and 4b each arranged between endpart 1 or 2 and the interpart 3. The inside surface 5 of each shell hasthe shape of a bilobate epitrochoid. In each shell, a piston, not shown,is arranged eccentrically rotatable, which together with the insidesurface 5 bounds three working spaces of varying volume, in each ofwhich. a complete four-stroke cycle is effected. In each shell, anintake passage 6 to supply a fuel-air mixture, two spark plugs 7 and anexhaust passage 8 to carry off the burned gases are provided. Inservice, the housing is subjected to heating that varies greatly overthe circumference, since in the sector from intake passage 6 to sparkplugs 7 the intake and compression phase always occurs, and in thesector from spark plugs 7 to exhaust passage 8 the expansion and exhauststroke alwaysoccurs. To achieve a housing temperature as uniform aspossible over the circumference, it is, therefore, necessary that thesector last mentioned be cooled very intensively, while the sector firstmentioned needs little or no cooling. Effective cooling near the sparkplugs 7 is especially important, since empirically this is where theheat load is greatest. Effective cooling of the shells is likewiseespecially critical, while the cooling of the end parts and interpartpresents no particular problem.

Each shell 4a, 4b, in the example of this embodiment, has three chambers9, 10, and 11, traversed successively by cooling liquid as will bedescribed later. Chamber 9 is arranged in the sector of the spark plugs7, chamber 10 in the following sector towards the exhaust passage 8, andchamber 11 in the sector of the exhaust passage 8. From each of thesechambers, ports open into the two end walls of each shell, namely ports12 and 13 for chamber 9, ports 14 and 15 for chamber 10 and ports 16 and17 for chamber 11. In addition, each shell 4 is provided with a throughpassage 18 to return the coolant after traversing the shells. End part 1has a hole 19 to accommodate a water pump 20 with flow volume regulator,connected by a line 21 to a liquid cooler, not shown. The liquiddelivered by pump 20 enters a chamber 22 in end part 1 and thencethrough ports 23, matching ports 12 and then passes into chamber 9 ofthe first shell 4a. In interpart 3, a chamber 24 is provided, whoseports 24a connect the ports 13 of the first shell 4a with ports 12 ofthe second shell 4b. After passing through chamber 9 of the second shell4b, the cooling liquid passes through the ports 13 of this shell andports 25 matching them in the adjoining end wall of end part 2 into achamber 26 in this end part where the cooling liquid is reversed and canpass through ports 27 in the wall of end part 2 and ports 15 in thesecond shell 4b into the chamber 10 of this shell. The ports 14 in theother end of shell 4b communicate through a chamber 28 and ports 28a ininterpart 3 with the ports 15 in the first shell 4a, so that the coolingliquid can traverse chamber 10 of the first shell 4a and pass throughports 14 and matching ports 29 in the adjoining wall of end part 1 intoa chamber 30 in end part 1. In chamber 30, the cooling liquid isreversed again, passing through ports 31 and matching ports 16 in thefirst shell 4a into the chamber 1 1 of this shell. Now the liquid leaveschamber 11 through ports 17 and their matching ports 32 into a chamber33 of interpart 3, communicating through ports 34 with the ports 16 inthe second shell 4b and through ports 35 with the passages 18 in shell4a and 4b. Some vof the liquid coming in from the chamber 1 1 of thefirst shell 4a passes through ports 34 and 16 into chamber 1 l of thesecond through one port 35 into the passage 18 of shell 4a.

From the chamber 11 of the second shell 4b, the liquid passes throughports 17 and their matching ports 36 in the adjoining wall of end part 2into a chamber 37 in this end part, communicating through a port 38 withthe passage 18 of the adjoining shell 4b. The passage 18 of the firstshell 40 opens into a return chamber 39 in the first end part 1,communicating by a line 40 with the other end of the liquid cooler, notshown, and through a by-pass 41 controlled by the flow control valve inpump-20 with the chamber 22 in end part 1.

The cooling liquid thus flows into the chamber 22 of end part 1,successively traverses the chambers 9 of shells 4a and 4b, is reversedby chamber 26 in end part 2, traverses the chambers 10 of the shells, isagain reversed by chamber 30 inthe first end part 1, traverses thechamber 11 of the first shell 4a, is divided at that point into twoparallel flows one of which is routed through chamber 33 in interpart 3and port 35 into the passage 18 of shell 4a and the other through thechamber 11 of the second shell 4b, thence to flow into chamber 37 of endpart 2 and drain off through port 38 and the passages 18.

To avoid leakage of cooling liquid out of the several ports along thejoining end faces of the shells, end parts and interpart, these portsare sealed individually by packing rings 42 (FIG. 6) arranged in annularrecesses 43 around the individual ports in the end faces of shells 4aand 4b. End parts 1 and 2, interpart 3 and shells 4a and 4b are heldtogether in conventional manner by through bolts (not shown), pressingthe packing rings 42 tight against the adjoining end walls of end parts1 2 and interpart 3.

If the internal combustion engine serves to propel a motor vehicle, itis expedient to arrange the lengthwise centerline of the housingparallel to the vehicle centerline, with the left-hand end of thehousing in FIG. 1 in the direction of travel. If the pistons of therotary piston internal combustion engine are oil cooled, the oil cooleris arranged in the airstream and connected to passages 44, 45' leadingfrom chamber 30 in the first end part 1 and thus traversed by thecooling liquid. To connect a vehicle heating system, two passages 46, 47may be provided in the second end part 2, of which passage 46 leads fromchamber 26 and supplies hot water to the heat exchanger of the heatingsystem and passage 47 carries the water, after traversing the heatexchanger, into the chamber 37 of end part 1 communicating with thereturn. This affords the maximum pressure differential between the inletand outlet sides of the heat exchanger, so that it is traversed at highflow velocity and the heating system responds very quickly.

As aforementioned, after passing through the chamber 11 of the firstshell 4a the cooling liquid flow is divided into two parts, so that thecooling liquid is returned in parallel streams. This keeps theflowresistance of the entire return circuit from taking too high a value.This is especially important in engines where more than two units areplaced in tandem.

The invention is not limited to the embodiment shown by way of example,in particular not to a twounit engine. Rather the invention may beapplied with the like advantages to an engine having only one shell orto an engine havingmore than two shells and a corresponding largernumber of interparts.

We claim:

1. A rotary piston engine having liquid cooled housing consisting of atleast one annular shell and two end parts, the housing having an inletand an outlet connection for a coolant liquid and the shell and endparts containing chambers in communication with each other, a coolantliquid, where the coolant liquid flows axially through the passages ofthe shell, means for reversing the flow .of the liquid in the chambersof the end parts, and the coolant liquid ports in the joining faces ofthe shell and end parts being sealed individualiy by means of packingrings encircling such ports.

2. The invention in accordance with claim 1 wherein a multiple rotarypiston engine is provided having a plurality of shells, a housinginterpart being arranged in each instance between neighboring shells,chambers are provided in the interpan connecting the chambers of theneighboring shells with each other, the coolant liquid ports in thejoining faces of the shells and interpart being individually sealed bymeans of packing rings encircling said ports.

3. A liquid cooled housing according to claim 2 wherein a chamber isprovided in the interpart to divert some of the cooling liquid coming inout of the chamber embracing the exhaust passage of one of the adjoiningshells.

4. A liquid cooled housing for rotary piston engines consisting of atleast one annular shell and two end parts, the housing having an inletand an outlet connection for a coolant liquid and the shell and endparts containing chambers in communication with each other, a coolantliquid, where the coolant liquid flows axially through the passages ofthe shell, and means for reversing the flow of the coolant liquid in thechambers of the end parts, the coolant liquid ports in the joining facesof the shell and end parts being sealed individually by means of packingrings encircling such ports, a spark plug sector and an exhaust passage,the chambers of the shell being connected in series by the chambers ofthe end parts in such manner that first the spark plug sector, then thesector following towards the exhaust passage, and then the sector aroundthe exhaust passage are traversed by cooling liquid.

5. The invention in accordance with claim 4 wherein the engine is forvehicle propulsion and includes a heat exchanger of a vehicle heatingsystem wherein a supply connection for the heat exchanger of a'vehicleheating system branches off from the chamber of that end part whicheffects the first reversal of the liquid, the outlet connection of theheat exchanger communicating with the return of the coolant liquidcircuit.

1. A rotary piston engine having liquid cooled housing consisting of atleast one annular shell and two end parts, the housing having an inletand an outlet connection for a coolant liquid and the shell and endparts containing chambers in communication with each other, a coolantliquid, where the coolant liquid flows axially through the passages ofthe shell, means for reversing the flow of the liquid in the chambers ofthe end parts, and the coolant liquid ports in the joining faces of theshell and end parts being sealed individually by means of packing ringsencircling such ports.
 2. The invention in accordance with claim 1wherein a multiple rotary piston engine is provided having a pluralityof shells, a housing interpart being arranged in each instance betweenneighboring shells, chambers are provided in the interpart connectingthe chambers of the neighboring shells with eacH other, the coolantliquid ports in the joining faces of the shells and interpart beingindividually sealed by means of packing rings encircling said ports. 3.A liquid cooled housing according to claim 2 wherein a chamber isprovided in the interpart to divert some of the cooling liquid coming inout of the chamber embracing the exhaust passage of one of the adjoiningshells.
 4. A liquid cooled housing for rotary piston engines consistingof at least one annular shell and two end parts, the housing having aninlet and an outlet connection for a coolant liquid and the shell andend parts containing chambers in communication with each other, acoolant liquid, where the coolant liquid flows axially through thepassages of the shell, and means for reversing the flow of the coolantliquid in the chambers of the end parts, the coolant liquid ports in thejoining faces of the shell and end parts being sealed individually bymeans of packing rings encircling such ports, a spark plug sector and anexhaust passage, the chambers of the shell being connected in series bythe chambers of the end parts in such manner that first the spark plugsector, then the sector following towards the exhaust passage, and thenthe sector around the exhaust passage are traversed by cooling liquid.5. The invention in accordance with claim 4 wherein the engine is forvehicle propulsion and includes a heat exchanger of a vehicle heatingsystem wherein a supply connection for the heat exchanger of a vehicleheating system branches off from the chamber of that end part whicheffects the first reversal of the liquid, the outlet connection of theheat exchanger communicating with the return of the coolant liquidcircuit.